[MIDI] Make android MIDI port id unique

media/midi/midi_manager_usb.cc

Index: media/midi/midi_manager_usb.cc
diff --git a/media/midi/midi_manager_usb.cc b/media/midi/midi_manager_usb.cc
index f2cf866aa0c68b36a8807b071817335369d33d65..8385d9fd79e1a55b6d5ddd5a4468b6f09ddc8ad7 100644
--- a/media/midi/midi_manager_usb.cc
+++ b/media/midi/midi_manager_usb.cc
@@ -8,6 +8,7 @@
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
+#include "base/strings/stringprintf.h"
 #include "media/midi/usb_midi_descriptor_parser.h"
 #include "media/midi/usb_midi_device.h"
 #include "media/midi/usb_midi_input_stream.h"
@@ -94,12 +95,16 @@ void MidiManagerUsb::OnEnumerateDevicesDone(bool result,
       if (jacks[j].direction() == UsbMidiJack::DIRECTION_OUT) {
         output_streams_.push_back(new UsbMidiOutputStream(jacks[j]));
         // TODO(yhirano): Set appropriate properties.
-        AddOutputPort(MidiPortInfo());
+        MidiPortInfo port;
+        port.id = base::StringPrintf("port-%zu-%zu", i, j);

[Takashi Toyoshima, 2014/08/28 11:52:11]

I might be wrong, but the i and j mean the USB port location right?
I forget what is this, so maybe adding some comments here will be helpful:)

If it is easy to use USB PID/VID in addition to USB port location here? It is
not mandatory, but would be better.

[yhirano, 2014/08/28 13:09:14]

They are just indices and are not meaningful. I will add PID/VID, but the USB
descriptor parser need to be fixed for it, so as a quirk I would propose this
CL.
Why I want to fix it now is, I am introducing MIDIInputMap and MIDIOutputMap.
Previously, duplicated IDs were no harm (while it violated the spec), but when
MIDIInputMap and MIDIOutMap are introduced duplicated IDs will be a serious
problem because they will be used as keys.

+        AddOutputPort(port);
       } else {
         DCHECK_EQ(jacks[j].direction(), UsbMidiJack::DIRECTION_IN);
         input_jacks.push_back(jacks[j]);
         // TODO(yhirano): Set appropriate properties.
-        AddInputPort(MidiPortInfo());
+        MidiPortInfo port;
+        port.id = base::StringPrintf("port-%zu-%zu", i, j);
+        AddInputPort(port);
       }
     }
     input_stream_.reset(new UsbMidiInputStream(input_jacks, this));